drivers/iio/adc/ti-adc12138.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * ADC12130/ADC12132/ADC12138 12-bit plus sign ADC driver
   4  *
   5  * Copyright (c) 2016 Akinobu Mita <akinobu.mita@gmail.com>
   6  *
   7  * Datasheet: http://www.ti.com/lit/ds/symlink/adc12138.pdf
   8  */
   9
  10 #include <linux/module.h>
  11 #include <linux/interrupt.h>
  12 #include <linux/completion.h>
  13 #include <linux/clk.h>
  14 #include <linux/property.h>
  15 #include <linux/spi/spi.h>
  16 #include <linux/iio/iio.h>
  17 #include <linux/iio/buffer.h>
  18 #include <linux/iio/trigger.h>
  19 #include <linux/iio/triggered_buffer.h>
  20 #include <linux/iio/trigger_consumer.h>
  21 #include <linux/regulator/consumer.h>
  22
  23 #define ADC12138_MODE_AUTO_CAL                  0x08
  24 #define ADC12138_MODE_READ_STATUS               0x0c
  25 #define ADC12138_MODE_ACQUISITION_TIME_6        0x0e
  26 #define ADC12138_MODE_ACQUISITION_TIME_10       0x4e
  27 #define ADC12138_MODE_ACQUISITION_TIME_18       0x8e
  28 #define ADC12138_MODE_ACQUISITION_TIME_34       0xce
  29
  30 #define ADC12138_STATUS_CAL                     BIT(6)
  31
  32 enum {
  33         adc12130,
  34         adc12132,
  35         adc12138,
  36 };
  37
  38 struct adc12138 {
  39         struct spi_device *spi;
  40         unsigned int id;
  41         /* conversion clock */
  42         struct clk *cclk;
  43         /* positive analog voltage reference */
  44         struct regulator *vref_p;
  45         /* negative analog voltage reference */
  46         struct regulator *vref_n;
  47         struct mutex lock;
  48         struct completion complete;
  49         /* The number of cclk periods for the S/H's acquisition time */
  50         unsigned int acquisition_time;
  51         /*
  52          * Maximum size needed: 16x 2 bytes ADC data + 8 bytes timestamp.
  53          * Less may be need if not all channels are enabled, as long as
  54          * the 8 byte alignment of the timestamp is maintained.
  55          */
  56         __be16 data[20] __aligned(8);
  57
  58         u8 tx_buf[2] __aligned(IIO_DMA_MINALIGN);
  59         u8 rx_buf[2];
  60 };
  61
  62 #define ADC12138_VOLTAGE_CHANNEL(chan)                                  \
  63         {                                                               \
  64                 .type = IIO_VOLTAGE,                                    \
  65                 .indexed = 1,                                           \
  66                 .channel = chan,                                        \
  67                 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),           \
  68                 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE)    \
  69                                         | BIT(IIO_CHAN_INFO_OFFSET),    \
  70                 .scan_index = chan,                                     \
  71                 .scan_type = {                                          \
  72                         .sign = 's',                                    \
  73                         .realbits = 13,                                 \
  74                         .storagebits = 16,                              \
  75                         .shift = 3,                                     \
  76                         .endianness = IIO_BE,                           \
  77                 },                                                      \
  78         }
  79
  80 #define ADC12138_VOLTAGE_CHANNEL_DIFF(chan1, chan2, si)                 \
  81         {                                                               \
  82                 .type = IIO_VOLTAGE,                                    \
  83                 .indexed = 1,                                           \
  84                 .channel = (chan1),                                     \
  85                 .channel2 = (chan2),                                    \
  86                 .differential = 1,                                      \
  87                 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),           \
  88                 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE)    \
  89                                         | BIT(IIO_CHAN_INFO_OFFSET),    \
  90                 .scan_index = si,                                       \
  91                 .scan_type = {                                          \
  92                         .sign = 's',                                    \
  93                         .realbits = 13,                                 \
  94                         .storagebits = 16,                              \
  95                         .shift = 3,                                     \
  96                         .endianness = IIO_BE,                           \
  97                 },                                                      \
  98         }
  99
 100 static const struct iio_chan_spec adc12132_channels[] = {
 101         ADC12138_VOLTAGE_CHANNEL(0),
 102         ADC12138_VOLTAGE_CHANNEL(1),
 103         ADC12138_VOLTAGE_CHANNEL_DIFF(0, 1, 2),
 104         ADC12138_VOLTAGE_CHANNEL_DIFF(1, 0, 3),
 105         IIO_CHAN_SOFT_TIMESTAMP(4),
 106 };
 107
 108 static const struct iio_chan_spec adc12138_channels[] = {
 109         ADC12138_VOLTAGE_CHANNEL(0),
 110         ADC12138_VOLTAGE_CHANNEL(1),
 111         ADC12138_VOLTAGE_CHANNEL(2),
 112         ADC12138_VOLTAGE_CHANNEL(3),
 113         ADC12138_VOLTAGE_CHANNEL(4),
 114         ADC12138_VOLTAGE_CHANNEL(5),
 115         ADC12138_VOLTAGE_CHANNEL(6),
 116         ADC12138_VOLTAGE_CHANNEL(7),
 117         ADC12138_VOLTAGE_CHANNEL_DIFF(0, 1, 8),
 118         ADC12138_VOLTAGE_CHANNEL_DIFF(1, 0, 9),
 119         ADC12138_VOLTAGE_CHANNEL_DIFF(2, 3, 10),
 120         ADC12138_VOLTAGE_CHANNEL_DIFF(3, 2, 11),
 121         ADC12138_VOLTAGE_CHANNEL_DIFF(4, 5, 12),
 122         ADC12138_VOLTAGE_CHANNEL_DIFF(5, 4, 13),
 123         ADC12138_VOLTAGE_CHANNEL_DIFF(6, 7, 14),
 124         ADC12138_VOLTAGE_CHANNEL_DIFF(7, 6, 15),
 125         IIO_CHAN_SOFT_TIMESTAMP(16),
 126 };
 127
 128 static int adc12138_mode_programming(struct adc12138 *adc, u8 mode,
 129                                      void *rx_buf, int len)
 130 {
 131         struct spi_transfer xfer = {
 132                 .tx_buf = adc->tx_buf,
 133                 .rx_buf = adc->rx_buf,
 134                 .len = len,
 135         };
 136         int ret;
 137
 138         /* Skip unused bits for ADC12130 and ADC12132 */
 139         if (adc->id != adc12138)
 140                 mode = (mode & 0xc0) | ((mode & 0x0f) << 2);
 141
 142         adc->tx_buf[0] = mode;
 143
 144         ret = spi_sync_transfer(adc->spi, &xfer, 1);
 145         if (ret)
 146                 return ret;
 147
 148         memcpy(rx_buf, adc->rx_buf, len);
 149
 150         return 0;
 151 }
 152
 153 static int adc12138_read_status(struct adc12138 *adc)
 154 {
 155         u8 rx_buf[2];
 156         int ret;
 157
 158         ret = adc12138_mode_programming(adc, ADC12138_MODE_READ_STATUS,
 159                                         rx_buf, 2);
 160         if (ret)
 161                 return ret;
 162
 163         return (rx_buf[0] << 1) | (rx_buf[1] >> 7);
 164 }
 165
 166 static int __adc12138_start_conv(struct adc12138 *adc,
 167                                  struct iio_chan_spec const *channel,
 168                                  void *data, int len)
 169
 170 {
 171         static const u8 ch_to_mux[] = { 0, 4, 1, 5, 2, 6, 3, 7 };
 172         u8 mode = (ch_to_mux[channel->channel] << 4) |
 173                   (channel->differential ? 0 : 0x80);
 174
 175         return adc12138_mode_programming(adc, mode, data, len);
 176 }
 177
 178 static int adc12138_start_conv(struct adc12138 *adc,
 179                                struct iio_chan_spec const *channel)
 180 {
 181         u8 trash;
 182
 183         return __adc12138_start_conv(adc, channel, &trash, 1);
 184 }
 185
 186 static int adc12138_start_and_read_conv(struct adc12138 *adc,
 187                                         struct iio_chan_spec const *channel,
 188                                         __be16 *data)
 189 {
 190         return __adc12138_start_conv(adc, channel, data, 2);
 191 }
 192
 193 static int adc12138_read_conv_data(struct adc12138 *adc, __be16 *value)
 194 {
 195         /* Issue a read status instruction and read previous conversion data */
 196         return adc12138_mode_programming(adc, ADC12138_MODE_READ_STATUS,
 197                                          value, sizeof(*value));
 198 }
 199
 200 static int adc12138_wait_eoc(struct adc12138 *adc, unsigned long timeout)
 201 {
 202         if (!wait_for_completion_timeout(&adc->complete, timeout))
 203                 return -ETIMEDOUT;
 204
 205         return 0;
 206 }
 207
 208 static int adc12138_adc_conversion(struct adc12138 *adc,
 209                                    struct iio_chan_spec const *channel,
 210                                    __be16 *value)
 211 {
 212         int ret;
 213
 214         reinit_completion(&adc->complete);
 215
 216         ret = adc12138_start_conv(adc, channel);
 217         if (ret)
 218                 return ret;
 219
 220         ret = adc12138_wait_eoc(adc, msecs_to_jiffies(100));
 221         if (ret)
 222                 return ret;
 223
 224         return adc12138_read_conv_data(adc, value);
 225 }
 226
 227 static int adc12138_read_raw(struct iio_dev *iio,
 228                              struct iio_chan_spec const *channel, int *value,
 229                              int *shift, long mask)
 230 {
 231         struct adc12138 *adc = iio_priv(iio);
 232         int ret;
 233         __be16 data;
 234
 235         switch (mask) {
 236         case IIO_CHAN_INFO_RAW:
 237                 mutex_lock(&adc->lock);
 238                 ret = adc12138_adc_conversion(adc, channel, &data);
 239                 mutex_unlock(&adc->lock);
 240                 if (ret)
 241                         return ret;
 242
 243                 *value = sign_extend32(be16_to_cpu(data) >> channel->scan_type.shift,
 244                                        channel->scan_type.realbits - 1);
 245
 246                 return IIO_VAL_INT;
 247         case IIO_CHAN_INFO_SCALE:
 248                 ret = regulator_get_voltage(adc->vref_p);
 249                 if (ret < 0)
 250                         return ret;
 251                 *value = ret;
 252
 253                 if (!IS_ERR(adc->vref_n)) {
 254                         ret = regulator_get_voltage(adc->vref_n);
 255                         if (ret < 0)
 256                                 return ret;
 257                         *value -= ret;
 258                 }
 259
 260                 /* convert regulator output voltage to mV */
 261                 *value /= 1000;
 262                 *shift = channel->scan_type.realbits - 1;
 263
 264                 return IIO_VAL_FRACTIONAL_LOG2;
 265         case IIO_CHAN_INFO_OFFSET:
 266                 if (!IS_ERR(adc->vref_n)) {
 267                         *value = regulator_get_voltage(adc->vref_n);
 268                         if (*value < 0)
 269                                 return *value;
 270                 } else {
 271                         *value = 0;
 272                 }
 273
 274                 /* convert regulator output voltage to mV */
 275                 *value /= 1000;
 276
 277                 return IIO_VAL_INT;
 278         }
 279
 280         return -EINVAL;
 281 }
 282
 283 static const struct iio_info adc12138_info = {
 284         .read_raw = adc12138_read_raw,
 285 };
 286
 287 static int adc12138_init(struct adc12138 *adc)
 288 {
 289         int ret;
 290         int status;
 291         u8 mode;
 292         u8 trash;
 293
 294         reinit_completion(&adc->complete);
 295
 296         ret = adc12138_mode_programming(adc, ADC12138_MODE_AUTO_CAL, &trash, 1);
 297         if (ret)
 298                 return ret;
 299
 300         /* data output at this time has no significance */
 301         status = adc12138_read_status(adc);
 302         if (status < 0)
 303                 return status;
 304
 305         adc12138_wait_eoc(adc, msecs_to_jiffies(100));
 306
 307         status = adc12138_read_status(adc);
 308         if (status & ADC12138_STATUS_CAL) {
 309                 dev_warn(&adc->spi->dev,
 310                         "Auto Cal sequence is still in progress: %#x\n",
 311                         status);
 312                 return -EIO;
 313         }
 314
 315         switch (adc->acquisition_time) {
 316         case 6:
 317                 mode = ADC12138_MODE_ACQUISITION_TIME_6;
 318                 break;
 319         case 10:
 320                 mode = ADC12138_MODE_ACQUISITION_TIME_10;
 321                 break;
 322         case 18:
 323                 mode = ADC12138_MODE_ACQUISITION_TIME_18;
 324                 break;
 325         case 34:
 326                 mode = ADC12138_MODE_ACQUISITION_TIME_34;
 327                 break;
 328         default:
 329                 return -EINVAL;
 330         }
 331
 332         return adc12138_mode_programming(adc, mode, &trash, 1);
 333 }
 334
 335 static irqreturn_t adc12138_trigger_handler(int irq, void *p)
 336 {
 337         struct iio_poll_func *pf = p;
 338         struct iio_dev *indio_dev = pf->indio_dev;
 339         struct adc12138 *adc = iio_priv(indio_dev);
 340         __be16 trash;
 341         int ret;
 342         int scan_index;
 343         int i = 0;
 344
 345         mutex_lock(&adc->lock);
 346
 347         iio_for_each_active_channel(indio_dev, scan_index) {
 348                 const struct iio_chan_spec *scan_chan =
 349                                 &indio_dev->channels[scan_index];
 350
 351                 reinit_completion(&adc->complete);
 352
 353                 ret = adc12138_start_and_read_conv(adc, scan_chan,
 354                                         i ? &adc->data[i - 1] : &trash);
 355                 if (ret) {
 356                         dev_warn(&adc->spi->dev,
 357                                  "failed to start conversion\n");
 358                         goto out;
 359                 }
 360
 361                 ret = adc12138_wait_eoc(adc, msecs_to_jiffies(100));
 362                 if (ret) {
 363                         dev_warn(&adc->spi->dev, "wait eoc timeout\n");
 364                         goto out;
 365                 }
 366
 367                 i++;
 368         }
 369
 370         if (i) {
 371                 ret = adc12138_read_conv_data(adc, &adc->data[i - 1]);
 372                 if (ret) {
 373                         dev_warn(&adc->spi->dev,
 374                                  "failed to get conversion data\n");
 375                         goto out;
 376                 }
 377         }
 378
 379         iio_push_to_buffers_with_timestamp(indio_dev, adc->data,
 380                                            iio_get_time_ns(indio_dev));
 381 out:
 382         mutex_unlock(&adc->lock);
 383
 384         iio_trigger_notify_done(indio_dev->trig);
 385
 386         return IRQ_HANDLED;
 387 }
 388
 389 static irqreturn_t adc12138_eoc_handler(int irq, void *p)
 390 {
 391         struct iio_dev *indio_dev = p;
 392         struct adc12138 *adc = iio_priv(indio_dev);
 393
 394         complete(&adc->complete);
 395
 396         return IRQ_HANDLED;
 397 }
 398
 399 static int adc12138_probe(struct spi_device *spi)
 400 {
 401         struct iio_dev *indio_dev;
 402         struct adc12138 *adc;
 403         int ret;
 404
 405         indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*adc));
 406         if (!indio_dev)
 407                 return -ENOMEM;
 408
 409         adc = iio_priv(indio_dev);
 410         adc->spi = spi;
 411         adc->id = spi_get_device_id(spi)->driver_data;
 412         mutex_init(&adc->lock);
 413         init_completion(&adc->complete);
 414
 415         indio_dev->name = spi_get_device_id(spi)->name;
 416         indio_dev->info = &adc12138_info;
 417         indio_dev->modes = INDIO_DIRECT_MODE;
 418
 419         switch (adc->id) {
 420         case adc12130:
 421         case adc12132:
 422                 indio_dev->channels = adc12132_channels;
 423                 indio_dev->num_channels = ARRAY_SIZE(adc12132_channels);
 424                 break;
 425         case adc12138:
 426                 indio_dev->channels = adc12138_channels;
 427                 indio_dev->num_channels = ARRAY_SIZE(adc12138_channels);
 428                 break;
 429         default:
 430                 return -EINVAL;
 431         }
 432
 433         ret = device_property_read_u32(&spi->dev, "ti,acquisition-time",
 434                                        &adc->acquisition_time);
 435         if (ret)
 436                 adc->acquisition_time = 10;
 437
 438         adc->cclk = devm_clk_get(&spi->dev, NULL);
 439         if (IS_ERR(adc->cclk))
 440                 return PTR_ERR(adc->cclk);
 441
 442         adc->vref_p = devm_regulator_get(&spi->dev, "vref-p");
 443         if (IS_ERR(adc->vref_p))
 444                 return PTR_ERR(adc->vref_p);
 445
 446         adc->vref_n = devm_regulator_get_optional(&spi->dev, "vref-n");
 447         if (IS_ERR(adc->vref_n)) {
 448                 /*
 449                  * Assume vref_n is 0V if an optional regulator is not
 450                  * specified, otherwise return the error code.
 451                  */
 452                 ret = PTR_ERR(adc->vref_n);
 453                 if (ret != -ENODEV)
 454                         return ret;
 455         }
 456
 457         ret = devm_request_irq(&spi->dev, spi->irq, adc12138_eoc_handler,
 458                                IRQF_TRIGGER_RISING, indio_dev->name, indio_dev);
 459         if (ret)
 460                 return ret;
 461
 462         ret = clk_prepare_enable(adc->cclk);
 463         if (ret)
 464                 return ret;
 465
 466         ret = regulator_enable(adc->vref_p);
 467         if (ret)
 468                 goto err_clk_disable;
 469
 470         if (!IS_ERR(adc->vref_n)) {
 471                 ret = regulator_enable(adc->vref_n);
 472                 if (ret)
 473                         goto err_vref_p_disable;
 474         }
 475
 476         ret = adc12138_init(adc);
 477         if (ret)
 478                 goto err_vref_n_disable;
 479
 480         spi_set_drvdata(spi, indio_dev);
 481
 482         ret = iio_triggered_buffer_setup(indio_dev, NULL,
 483                                          adc12138_trigger_handler, NULL);
 484         if (ret)
 485                 goto err_vref_n_disable;
 486
 487         ret = iio_device_register(indio_dev);
 488         if (ret)
 489                 goto err_buffer_cleanup;
 490
 491         return 0;
 492 err_buffer_cleanup:
 493         iio_triggered_buffer_cleanup(indio_dev);
 494 err_vref_n_disable:
 495         if (!IS_ERR(adc->vref_n))
 496                 regulator_disable(adc->vref_n);
 497 err_vref_p_disable:
 498         regulator_disable(adc->vref_p);
 499 err_clk_disable:
 500         clk_disable_unprepare(adc->cclk);
 501
 502         return ret;
 503 }
 504
 505 static void adc12138_remove(struct spi_device *spi)
 506 {
 507         struct iio_dev *indio_dev = spi_get_drvdata(spi);
 508         struct adc12138 *adc = iio_priv(indio_dev);
 509
 510         iio_device_unregister(indio_dev);
 511         iio_triggered_buffer_cleanup(indio_dev);
 512         if (!IS_ERR(adc->vref_n))
 513                 regulator_disable(adc->vref_n);
 514         regulator_disable(adc->vref_p);
 515         clk_disable_unprepare(adc->cclk);
 516 }
 517
 518 static const struct of_device_id adc12138_dt_ids[] = {
 519         { .compatible = "ti,adc12130", },
 520         { .compatible = "ti,adc12132", },
 521         { .compatible = "ti,adc12138", },
 522         { }
 523 };
 524 MODULE_DEVICE_TABLE(of, adc12138_dt_ids);
 525
 526 static const struct spi_device_id adc12138_id[] = {
 527         { "adc12130", adc12130 },
 528         { "adc12132", adc12132 },
 529         { "adc12138", adc12138 },
 530         { }
 531 };
 532 MODULE_DEVICE_TABLE(spi, adc12138_id);
 533
 534 static struct spi_driver adc12138_driver = {
 535         .driver = {
 536                 .name = "adc12138",
 537                 .of_match_table = adc12138_dt_ids,
 538         },
 539         .probe = adc12138_probe,
 540         .remove = adc12138_remove,
 541         .id_table = adc12138_id,
 542 };
 543 module_spi_driver(adc12138_driver);
 544
 545 MODULE_AUTHOR("Akinobu Mita <akinobu.mita@gmail.com>");
 546 MODULE_DESCRIPTION("ADC12130/ADC12132/ADC12138 driver");
 547 MODULE_LICENSE("GPL v2");